Making more than three attempts to retrieve a thrombus in a patient with acute ischaemic stroke raises the risk of symptomatic intracerebral haemorrhage (ICH) three to four-fold, a registry study shows.

The findings may help neuro-interventionists to make the difficult decision of when to stop the procedure, particularly in patients with large infarcted areas, the German researchers say.

They looked at almost 600 patients from the German Stroke Registry who presented with large vessel occlusion in the anterior circulation, and for whom there was complete data, including on the number of passes during endovascular therapy either by aspiration, stent retrieval or both.

Participants had a mean age of 72 years, 51% were men, median National Institutes of Health Stroke Scale (NIHSS) was 15 at baseline (maximum and worst is 42) and median Alberta Stroke Program Early CT Score (ASPECTS) was nine (maximum and least severe is 10).